What Purpose Do Dreams Serve?
The topic is still hotly contested, but the leading position holds that dreams “help us process new, emotionally important information and add it to our conceptual memory system,” says Rosalind Cartwright, Ph.D, a psychologist and the founder of the Sleep Disorder Service and Research Center at Rush University Medical Center, in Chicago. Once the information is in your memory, it influences your waking behavior and decisions. For instance, research has revealed that dreams can:
Help you understand new experiences. REM dreams link new events to old ones, putting them in context. For example, if you’re feeling anxious about your job, you may dream about another anxious time, like when you were taking a test in college. “It’s almost like the old card-catalog system in libraries,” says David Linden, Ph.D., a professor of neuroscience at the Johns Hopkins University School of Medicine, in Baltimore. “Dreams consolidate our recent memories and cross-reference them with older ones so that we can better understand what’s going on. This explains why dreams so often incorporate elements from our past.”
Indeed, when scientists do brain scans on subjects during REM sleep, they find that the visual center of the brain, the dominant area that processes all the new information people encounter while awake, is shut down. The visual memory center, though―the part of the brain that stores images from the past, like what your childhood bedroom looked like―is in overdrive. This indicates that all the images we “see” during our dreams are being pulled from our memories, says Linden, who is also the author of The Accidental Mind: How Brain Evolution Has Given Us Love, Memory, Dreams, and God ($16, amazon.com). It’s almost as if your brain is taking a new experience and flipping through the old photo albums in your memory to find out where it fits, which ultimately may help you better understand it.
Prepare you for change. Dreams can be a rehearsal for new challenges. When a person in love dreams about weddings or an athlete dreams about competitions, this helps the dreamer mentally prepare for the future. Says Cartwright, “Your brain is taking this ‘emotionally hot’ material and helping you process it so that you can better deal with it when you’re awake.”
Help you cope with trauma or loss. Cartwright studied people going through divorces and found that those who were the most depressed in their waking lives had the flattest, least emotional dreams, while those who were managing well had highly expressive, furious dreams, complete with scenes of throwing objects at their soon-to-be exes. “It seemed like the people who were having a harder time adjusting were having the dullest dreams because they weren’t facing up to their emotions, while those who coped the best were working out their feelings in their dreams,” Cartwright says. “It was almost like their dreams helped them realize, ‘I’ve handled feelings like this before, so I can deal with them again.’”
Your dreams may change, though, as you begin to adjust to a loss. Deirdre Barrett, Ph.D., a clinical assistant professor of psychology at Harvard Medical School and the editor in chief of the scientific journal Dreaming, looked at the dreams of people who had lost loved ones. She found that dreams in the earliest stages of mourning were often back-to-life dreams, in which the dreamer was confused or upset by the appearance of the loved one. Dreams that occurred months or years after the person had died were more pleasant, with the deceased person telling the dreamer that everything was OK or sometimes giving advice. “These later dreams were reassuring, even comforting, to the dreamers, helping them to deal with their loss,” says Barrett.
Facilitate learning. Non-REM dreams, which tend to reflect the day’s events, may help us consolidate new information. In a series of studies being conducted at Harvard, sleep-lab subjects were asked to play the video game Tetris. Later, when woken during the first stage of sleep, of those who could recall their dreams, three-quarters were dreaming about Tetris. The researchers believe that by dreaming about the game, the subjects were working on perfecting their skills as they slept. The research team that conducted these studies has just completed similar ones using the skiing game Alpine Racer 2. The initial reports, published in the journal Science in 2001, stated that the people who were most involved while playing the game were the ones most apt to dream about it, suggesting that, while they slept, their brains were processing the information that seemed most important.